The invention relates to a method of applying a conductive, transparent metal-oxide layer to a surface of a substrate.
Such layers are applied, inter alia, to windows of cathode ray tubes. The conductive layer has an anti-static effect and a shielding effect, that is, the intensity of the electromagnetic stray field emitted by the cathode ray tube is reduced by applying said conductive transparent layer.
A method of the type mentioned in the opening paragraph is disclosed in WO 95/29501. In said document, a description is given of a method in which a sol/gel coating of ITO (indium-tin oxide, i.e. a layer containing SnO.sub.2 /In.sub.2 O.sub.3) is cured by means of a laser in a hydrogen-containing atmosphere. Within the scope of the invention, a conductive metal-oxide layer must be understood to mean a layer which comprises an oxide or oxides of a metal or of a mixture of metals and which is capable of conducting electric current.
As regards the known method and methods of applying conductive layers in general, the relatively high resistance and the instability of the conductive layer constitute a problem.
Although conductive layers manufactured in accordance with the known method have a lower resistance than conductive layers manufactured by earlier methods, their resistance is still relatively high for specific applications and they often exhibit, as a function of time, an instability in the conductivity. In general, the conductivity decreases as a function of time. A decrease in conductivity causes a reduction of the shielding and anti-static function of the conductive layer. A reduction of the resistance leads to an improvement of the shielding effect.